FILARIID.E 251 



mucosa, which is unaltered with the exception of an opening at the 

 tumor's sunnnit. Outwardly, they are limited by the muscular coat. 



Upon incision of the hardened tissue of the tumor it is found to contain 

 cavities which, on pressure, yield a purulent fluid with which are ex- 

 truded the parasites. A varying number of worms may be found coiled 

 up in these chambers, generally from two or three up to twenty. 



Symptoms and Course. — The most characteristic symptom of the 

 presence of this worm is persistent vomiting. A fatal termination may 

 be brought about from inanition resulting from the repeated vomiting, 

 or the gastric tumors may rupture upon the peritoneum and cause a 

 fatal peritonitis. 



Development. — Railliet has demonstrated that the eggs retain their 

 shells in their passage through the intestines of the dog and reach the 

 outside with the excrement. Researches of Grassi have shown that the 

 embryos then pass into the body of a cockroach, probably' by its feeding 

 upon the egg-containing excrement of infected dogs. In the bodj^-cavity 

 of this insect he found large cysts containing larval nematodes agreeing 

 in color with this species. The cysts were fed to dogs which, after two 

 weeks, showed on necropsy the young parasites alread}^ embedded in 

 the mucosa of the esophagus. Natural infection of dogs probably 

 occurs by their eating the roaches containing these cj^sts. 



Treatment. — In the absence of precise symptoms indicating the 

 presence of these worms, the diagnosis in practicalh' all cases being made 

 post-mortem, there is little to be said as to the treatment of the affec- 

 tion. Bismuth or small doses of cocaine may be given as palliative 

 treatment for the relief of the recurrent vomiting, 



FlLARIID^ OF THE HoG 



1. Arduenna strongylina (Spiroptera strongylina). Filariidae (p. 

 244). — The body is subcylindrical and often curved ina semicircle. The 

 anterior portion is attenuated, the posterior somewhat broader. The 

 cuticle is densely striated transversely. The mouth has two lateral 

 lips, each with three lobes leading into a small buccal capsule which is 

 followed by a cylindrical pharynx marked with cuticular ridges forming a 

 series of spirals. The caudal end of the male is curved, has two unequal 

 wings, and five pairs of stalked papillae asymmetrically arranged. The 

 spicules are long and very unequal. The vulva of the female is slightly 

 anterior to the middle of the body. 



Length of female, 16-22 mm. (5/8-7/8 of an inch); male, 10-15 mm. 

 (3/8-5/8 of an inch). 



The eggs are oval, 34-39 microns long by 20 microns wide. They 

 have thick shells and contain well-developed embryos at the time of 

 oviposition. 



